Starting from Linux 5.10 io_uring supports restrictions. This patch describes how to register restriction, enable io_uring ring, and potential errors returned by io_uring_register(2). Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx> --- v2: - fixed grammar issues [Jens] --- man/io_uring_register.2 | 79 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 77 insertions(+), 2 deletions(-) diff --git a/man/io_uring_register.2 b/man/io_uring_register.2 index 5022c03..225e461 100644 --- a/man/io_uring_register.2 +++ b/man/io_uring_register.2 @@ -19,7 +19,8 @@ io_uring_register \- register files or user buffers for asynchronous I/O The .BR io_uring_register () -system call registers user buffers or files for use in an +system call registers resources (e.g. user buffers, files, eventfd, +personality, restrictions) for use in an .BR io_uring (7) instance referenced by .IR fd . @@ -232,6 +233,58 @@ must be set to the id in question, and .I arg must be set to NULL. Available since 5.6. +.TP +.B IORING_REGISTER_ENABLE_RINGS +This operation enables an io_uring ring started in a disabled state +.RB (IORING_SETUP_R_DISABLED +was specified in the call to +.BR io_uring_setup (2)). +While the io_uring ring is disabled, submissions are not allowed and +registrations are not restricted. + +After the execution of this operation, the io_uring ring is enabled: +submissions and registration are allowed, but they will +be validated following the registered restrictions (if any). +This operation takes no argument, must be invoked with +.I arg +set to NULL and +.I nr_args +set to zero. Available since 5.10. + +.TP +.B IORING_REGISTER_RESTRICTIONS +.I arg +points to a +.I struct io_uring_restriction +array of +.I nr_args +entries. + +With an entry it is possible to allow an +.BR io_uring_register () +.I opcode, +or specify which +.I opcode +and +.I flags +of the submission queue entry are allowed, +or require certain +.I flags +to be specified (these flags must be set on each submission queue entry). + +All the restrictions must be submitted with a single +.BR io_uring_register () +call and they are handled as an allowlist (opcodes and flags not registered, +are not allowed). + +Restrictions can be registered only if the io_uring ring started in a disabled +state +.RB (IORING_SETUP_R_DISABLED +must be specified in the call to +.BR io_uring_setup (2)). + +Available since 5.10. + .SH RETURN VALUE On success, @@ -242,16 +295,30 @@ is set accordingly. .SH ERRORS .TP +.B EACCES +The +.I opcode +field is not allowed due to registered restrictions. +.TP .B EBADF One or more fds in the .I fd array are invalid. .TP +.B EBADFD +.B IORING_REGISTER_ENABLE_RINGS +or +.B IORING_REGISTER_RESTRICTIONS +was specified, but the io_uring ring is not disabled. +.TP .B EBUSY .B IORING_REGISTER_BUFFERS or .B IORING_REGISTER_FILES -was specified, but there were already buffers or files registered. +or +.B IORING_REGISTER_RESTRICTIONS +was specified, but there were already buffers, files, or restrictions +registered. .TP .B EFAULT buffer is outside of the process' accessible address space, or @@ -283,6 +350,14 @@ is non-zero or .I arg is non-NULL. .TP +.B EINVAL +.B IORING_REGISTER_RESTRICTIONS +was specified, but +.I nr_args +exceeds the maximum allowed number of restrictions or restriction +.I opcode +is invalid. +.TP .B EMFILE .B IORING_REGISTER_FILES was specified and -- 2.26.2
